For now, I will let Michael Walzer answer that question. Walzer is professor emeritus at the Institute for Advanced Study (IAS) in Princeton, New Jersey. He is also the co-editor or the leftist magazine Dissent.
In this clip, Walzer talks about the history of just war theory. He also addresses elements of his own thought on the matter. In the post-Vietnam-era, few have done more to advance just war theory than Michael Walzer.
Talk a listen:
(Source: Big Think)
For Walzer’s full treatment of just war theory, check out his classic treatise Just And Unjust Wars: A Moral Argument With Historical Illustrations.
Categories: Blog
approachingjustice.net 
Hi Chris
Why did God create human and universe?
Said Nursi gives answer to this question in his books
(Risalei Nur Collection):
Here an example:
In regard to his acts and deeds and his labour man is a weak
animal, an impotent creature. The extent of his power of disposal and ownership
in this respect is so narrow that it is no greater than as far as his hand can
reach. Domestic animals, even, the reins of which have been given to man, have
each taken a share of his weakness, impotence, and laziness, so that if they
are compared with their wild counterparts, a great difference apparent. (Like
domestic goats and cattle, and wild goats and cattle). But ii regard to
passivity, acceptance, supplication, and entreaty, man is an honoutd traveller
in this hostel of the world. He is the guest of One so generous ti.it infinite
treasuries of mercy have been opened to him and innumerable unjqae beings and
servants subjugated to him. And a sphere so large has been pepared for this
guest’s recreation, amusement, and benefit that half its dianeter is as long
and broad as the imagination can stretch.
http://www.nur.gen.tr/en.html#maincontent=Risale&islem=read&KitapId=456&BolumId=8520&KitapAd=The+Words&Page=332